The objective of the proposed program of studies is: (1) To further develop basic experimental knowledge of the pathogenetic mechanisms of virus-induced demyelinating disease, using the mouse hepatitis virus type 4 (MHV-4, JHM) model system to study the linkage of the gene for resistance to disease, the response of the target cell, the oligodendrocyte to infection in vitro, and the interactions of cells of the immune system during the course of demyelination and remyelination characteristic of this model. (2) To apply basic experimental knowledge of pathogenetic mechanisms in clincial investigations of human demyelinating and other neurological diseases in an effort to alter the course of such diseases. Peripheral blood lymphocytes, rich in activated suppressor lymphocytes, will be harvested and stored, to be used later to test their effectiveness in suppressing an exacerbation of multiple sclerosis. In addition, natural alpha interferon will continue to be evaluated as a potential therapeutic agent in multiple sclerosis, and cloned beta interferon will be evaluated for use through testing initially on patients with glioblastoma multiforme, and then extended to include severely affected multiple sclerosis patients.